An imminent increase in cadmium concentration in the environment imposes biological hazards on living organisms including human beings. In this proposed project, the effects of cadmium on reproduction in the rat will be studied. Cadmium contamination will be induced either by (1) a single subcutaneous injection of cadmium chloride (acute exposure) or (2) by intake of cadmium contaminated water (chronic exposure). Experiments are designed: (1) To study the dose and time dependent responses to cadmium chloride treatment on different parameters. Sexual drive, steroidogenesis, spermatogenesis, sperm number, morphology and fertilizing capacity in the male rat. Regularity of estrous cycle, ovulation, receptivity, conception rate, gestation length and steroidogenic capacity in the female rat. Morphological abnormalities, growth rate and reproductive performance in rats subjected to prenatal exposure of cadmium through maternal contamination of cadmium chloride and with or with no further postnatal exposure to cadmium. The same parameters will be studied in their offspring. (2) To examine dietary factors (low protein, low iron diet, high protein or high iron diet) on the modulation of cadmium chloride induced changes in the reproductive performance in both the female and male rat. (3) To explore a possible hormonal remedy to accident exposure to cadmium. Prolactin, prolactin plus LH, or testosterone will be tested as a protective agent to reduce the deleterious effects of cadmium chloride on reproductive performance in the male rat.